Diagnostic tests may require separation of a patient's whole blood sample into components, such as plasma or serum (i.e., the lighter phase component) and red blood cells (i.e., the heavier phase component). For example, a plasma sample may be tested using known amplification techniques to monitor the HIV RNA viral load of HIV infected patients to diagnose and manage the disease. A patient's response to approved drugs, new drugs and combination drug therapies can be evaluated by monitoring the patient's HIV RNA viral load. In addition to the HIV virus, there are a number of other infectious diseases that would benefit from viral load monitoring, such as the Hepatitis C virus.
Currently, plasma viral monitoring is typically performed by drawing samples of whole blood by venipuncture through a cannula or needle attached to a syringe or an evacuated collection tube. Separation of the blood into plasma and other cellular components, or into serum and red blood cells is then accomplished by spinning of the syringe or tube in a centrifuge. Such techniques typically use a barrier that moves between the two phases of the sample being separated, thereby maintaining the component separation for subsequent examination of the individual components. Typically, the samples must then be transported to a different location, such as a laboratory, where personnel conduct specific tests on the samples. Generally, a considerable amount of time elapses between obtaining the sample and analyzing it. A common and recurring problem, therefore, is the maintenance of the biological sample in a manner that prevents degradation, alteration or destruction of essential materials during the manipulations and/or preparations preceding analysis of the biological sample.
Currently, blood samples are collected in EDTA tubes and spun to obtain plasma. The plasma samples are then shipped in primary or secondary tubes on ice or under refrigerated conditions for further analysis. The cold temperature shipping reduces vRNA degradation.
A need exists for a standard device designed to collect, process, and transport plasma samples for use with amplification technologies. Most preferably, the device should be able to assist in standardizing specimen handling, provide a closed system, isolate the plasma from the cellular components, produce minimal plasma dilution, and minimize interference with the nucleic acid testing.